This invention relates to track laying vehicles, and in particular to conversion units for attachment to conventional powered vehicles to convert the latter to track laying vehicles.
The problem of conversion of a vehicle, such as an automobile, to a half-track vehicle has been addressed in the art. Typical prior patents are White Canadian Pat. No. 219,041, McNeill et al Canadian Pat. No. 403,861, Tolsma Canadian Pat. No. 215,937, Sedore et al Canadian Pat. No. 412,663, Christensen Canadian Pat. No. 631,722, Degroot U.S. Pat. No. 3,872,938, Copera et al U.S. Pat. No. 3,930,553, and Guibord et al U.S. Pat. No. 3,933,214.
The structure in Pat. No. 219,041 suffers from the disadvantage that substantial modification of the vehicle is required to install the tracks. In Pat. No. 215,937, substantial structure is required and once installed is difficult to remove, further, it requires substantial space beneath the vehicle and in front of the driven wheels. In Pat. No. 413,663, a permanent modification is made, substantial space is required beneath the vehicle for installation and the idler wheels apparently do not engage the ground. In Pat. No. 631,722, while the disclosed construction may be relatively simply attached to a tractor it is heavy and relatively complicated, thus being unsuitable for mass production, and a separate attachment is required for each track. U.S. Pat. No. 3,872,938 discloses a structure suitable for modification of a motorcycle, however, installation is difficult and time consuming, and the structure is designed for a single rear wheel, not lending itself to attachment to a vehicle with two rear wheels. Canadian Pat. No. 403,861 discloses a structure that can be secured to the frame of an automotive vehicle, in effect extending the frame, but it is a heavy duty construction and once installed would be difficult to remove, further, the patentee does not teach an effective spring system for the auxiliary wheels that support the track. U.S. Pat. No. 3,930,553 also discloses a permanent conversion unit, difficult to remove once installed. U.S. Pat. No. 3,933,214, while disclosing a half track attachment, teaches a complex structure, difficult to install, necessitating substantial modification of a vehicle.
The prior art fails to address the need for a lightweight conversion unit suitable for attachment to modern all terrain vehicles quickly and easily, without special tools, which is easily removed from the vehicle when it is desired to return the vehicle to its original intended use, and to which simple modifications can be made to make it suitable for a variety of different uses.